Day in Engineering History Archive - June 30

June 30

Special Relativity Published - RF Cafe1879: The California Electric Light Company was organized in San Francisco, becoming the first electric company formed to produce and sell electricity 1905: Albert Einstein published his theory on special relativity, "On the Electrodynamics of Moving Bodies." 1908: An unexplained explosion in Tunguska, Siberia knocked down trees in a 40-mile radius and knocked people unconscious 40 miles away. 1918: Francis Stanley, famous for his Stanley Steamer automobile, died. 1930: The first round-the-world broadcast from the U.S. used a series of short-wave radio relays and took one-eighth of a second. 1946: The first atomic bomb dropped from an airplane over water occurred over the Bikini Atoll onto a target group of 73 scrapped ships. 1948: The invention of the transistor was announced by Bell Laboratory. 1948: The first telephone recording devices were authorized for public use in the U.S., and required a periodic "beep" to alert the users. 1953: The first Corvette rolled off the Chevrolet assembly line (it sold for $3,250). 1961: Dr. Lee de Forest, inventor of the Audion tube, died. 1971: Three cosmonauts aboard Soyuz 11 were found dead inside their spacecraft after it had returned to Earth. 1972: The first leap second time correction was added. 1997: China resumed sovereignty over Hong Kong.

| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |

Note: These historical tidbits have been collected from various sources, mostly on the Internet. As detailed in this article, there is a lot of wrong information that is repeated hundreds of times because most websites do not validate with authoritative sources. On RF Cafe, events with hyperlinks have been verified. Many years ago, I began commemorating the birthdays of notable people and events with special RF Cafe logos. Where available, I like to use images from postage stamps from the country where the person or event occurred. Images used in the logos are often from open source websites like Wikipedia, and are specifically credited with a hyperlink back to the source where possible. Fair Use laws permit small samples of copyrighted content.